Android 8.0+ compatibility - reading WifiConfigStore.xml

[blinkingtwelve]

This adds Android 8.0+ compatibility, and fixes #1 .

Tested on Android 9 with the LineageOS AddonSU.

It reads both the wpa_supplicant.conf and the WifiConfigStore.xml files, if they exist, and merges the result. In the case of duplicate SSIDs the WifiConfigStore.xml will win - which makes sense, as in the case that both files are present we're probably running on an upgraded device, and then the latter is authoritative because it's the one in use.
Anyway, if one doesn't like seeing results from the one or the other, one can just set an invalid path in the settings.

I've also reworked and simplified the su wrapper. As su can take as a direct argument the command you want to run, spawn a root shell to which to "type" this command over stdin — the way it was done before, in ExecuteAsRootBase.java — is unnecessary. And as now there is no longer a shell involved, the new code is robust with respect to, say, characters in file paths which would previously need to be shell-escaped because the shell would split/interpret the argument otherwise. Actually, as any such escaping wasn't done before in ExecuteAsRootBase.java, the "WPA Supplicant File Path" setting up until now actually used to offer a way to run arbitrary shell commands as root 🦖 — of minor concern, since the user was probably only a confirmation dialog away from popping a root shell on their phone anyway 😄

[IzzySoft]

@aario just wondering, as you didn't respond here: are you still maintaining this app? If not, would you be willing to transfer maintenance to @blinkingtwelve? He has volunteered for that, we at F-Droid (I'm one of the maintainers there) would just need your confirmation for that. Development can continue in his fork if you prefer that, or you could make him a "member" here. In either case, credits will remain to you as the original developer of course 😉

[IzzySoft]

@aario any word?